Question

o triplo do triplo do dobro é 126

Answer 1

$3*3*2*x=126\\18x=126\\x= \frac{126}{18} =7$

Answer 2

$3~[3~(2x)]=126\to \\\\3~[6x]=126\to\\\\ 18x=126\to\\\\ x= \dfrac{126}{18} \to\\\\ \large\boxed{x=7}$